Ruptured Aneurysm of Right Sinus of Valsalva in Pregnancy-A Case Report

Summary A 26 year old multigravida at 36.6 weeks of gestation with ruptured aneurysm of right sinus of Valsalva was presented for caesarean section. Diagnosis was confirmed by transthoracic echocardiography. Here we present the anaesthetic management of this case posted for caesarean section.


Introduction
Aneurysm of a sinus of Valsalvais a rare congenital cardiac defect, first described by Hope in 1839. Thurnam in 1840 reported the first case of rupture of the sinus of Valsalva. 1 The clinical characteristics of aneurysm of sinus of Valsalva in cases described so far appear to be i More common in patients ofAsian Origin ii Male to female ratio is 3:1 iii Uncommon in infancyand childhood iv Comprises approximately 0.1-3.5% of all congenitalcardiac anomalies.
The mortality rate in patients with a sinus of Valsalva aneurysm in whom surgery is not performed is high within the first year afterrupture. Cases of sudden death from sinus of Valsalva aneurysm most commonly involve rupture of the aneurysm with the acute onset of overwhelming congestiveheart failure, cardiac tamponade, dysrhythmia, or coronary ischemia depending on the location of the aneurysm and the subsequent flow disturbance. Size and location of the shunt are the major determinants of presentation and prognosis.
There are few documented cases of ruptured an-eurysm of sinus of Valsalva in pregnancy. 1,2 Various management options have been reported i.e. caesarean section under general anaesthesia, 2 lumbar epiduralanaesthesia during induction of labor and caesarean delivery, 3 or normalvaginaldelivery under medicalsupervision. 4

Case report
A 26 year old, 50Kg, multigravida with 8 months of amenorrhea was admitted to our hospitalfor elective lower segment caesarean section (LSCS) and ligation. Thepatient presentedwith complaintsof breathlessness, chest painand occasionalpalpitation at rest sincelast 7-8months. She also complained swelling of both lower limbs which decreasesafter takingrest. Shehad normal vaginal delivery 3½ years back. There was history of onespontaneous abortion in the past. She complained of breathlessness and tiredness one year after vaginal deliveryfor which she consulted physician. Shewas informed that she has a heart disease andwas diagnosed as rupturedaneurysm of right sinusof Valsalva.She was advised to undergo surgical correction of the heart ailment. She was alsoadvised not to have pregnancy until her heart disease was corrected by surgery. But the patientcould not afford thesurgery andbecame pregnant. She was on oraldigoxin 0.25mgand frusemide 20 mg per day, five times a week.  On examination, her pulse rate was 96/minute, and B.P. 110/70 mm of Hg. Pittingtype ofpedaloedema was present. Respiratorysystem showedbilateralequal, normal vesicular breath sounds with no rhonchi or crepitations. On auscultation of cardiovascular system a loud continuous murmur was present over whole of the precordium. It was best heard along the lower left sternal border. Apalpable thrillwas present along the left sternal border. The remainder of the examination was otherwise normal for 36.6 weeks of pregnancy. Routine blood investigations were normal except Hb.(9gm %). Chest radiograph was normal. Electrocardiogram showed sinus tachycardia. Transthoracic echocardiography (TTE) showed a membranous out pouching of the right coronary cusp (RCC) protruding into right ventricle out flow tract (RVO) with a small (3.2 mm width) perforation ( Fig.1). There was continuous wave flow with a left to right (L-R) shunt into the right (RVO) tract below the pulmonary valve (Fig.2).The ventricular chambers were normal in size and there was good left ventricular function at rest (Fig.3).A diagnosis of perforated aneurysm of right sinus of Valsalva was confirmed. Patient was continued with oraldigoxin and lasix.
Patient was admitted forsafe confinementand for elective caesarean section keeping in mind her poor cardiac status. High riskconsent for anaesthesia was taken. The patient was kept fasting for six hours. The patient was shifted to operation room in propped up position breathingoxygen by apolymask. Intravenous access wasobtained. Intravenousranitidine 50 mg and metoclopramide 10mgwere given 30 minutes prior to induction foraspiration prophylaxis.Antibiotic prophylaxiswas obtainedwith 2gm ofintravenous amoxycillin. Monitoring ofpulse rate, electrocardiography, oxygen saturation, EtCO 2, urine output andnon-invasive blood pressure was started andcontinued throughout the surgery. Central venous access was obtained via the right internal jugular vein. Central venous pressure (CVP) was monitored throughout the surgery and was kept within normal limits. Rapid sequence induction was carried. Patient was preoxygenated with 100% oxygen for 5 minutes. Anaesthesia was induced with thiopentone sodium (1.25%)5mg.Kg -1 slowly, succinylcholine 80mg and i.v. lidocaine 1.5mg.Kg -1 . Patient was intubated with no.7.5 oral, cuffed endotracheal tube. Lungs were ventilated with 50% O 2 and 50% N 2 O and isoflurane (0.4%) till the birth of baby. Fifteen units of oxytocin were added to the Ringer lactate infusion after the baby was delivered. Anaesthesiawas maintained with O 2 +N 2 O in the ratio 50:50, isoflurane (0.4%-0.6%), vecuronium 0.08 mg / kg and i.v. fentanyl 100mcg. EtCO 2 was maintained around 36-40mm of Hg and CVP around 3-5 cm of water.

Discussion
A ruptured sinus of Valsalva aneurysm is a rare cardiac anomaly usually of a congenital nature. The sinuses of Valsalva are dilatations in the aortic wall immediately superior to the attachments of three aortic wall cusps. The sinuses are named accordingto their relationship with the coronary arteries: i.e. the right coronary sinus, the left coronary sinus, and the non coronary sinus. 5 Aneurysmaldilatation of the sinuses of Valsalva occurs when the aortic media is defective, resulting in lack of fusion between aortic media and annulus fibrosus of the aortic valve. 6 Aneurysm typically develops as a discrete flaw in the aortic media within one of the sinuses of Valsalva. Under the strain of aortic pressure, the sinus gradually weakens and dilates, causing the formation of an aneurysm. Lack of supporting tissue (e.g., ventricular septal defect) may contribute to instability and progressive distortion of the aortic sinus. Distortion and prolapse of the sinus and aortic valve tissue can lead to progressive aortic valve insufficiency. Othercases result from an inherited connective tissue abnormality, as in Marfan syndrome or Ehlers-Danlos syndrome; from inflammatory disease, as in endocarditis, syphilitic or granulomatous aortitis, or Behcet's disease; and from mechanical disruption after stab wounds, aortic dissection,or after aortic valve replacement or ventricular septaldefect repair.
Theright coronarysinus is the mostcommon site of aneurysm formation mostly ruptures into the right ventricle, producingleft to right shunting. 7 Right coronary sinus aneurysms may also rupture into the right atrium. Non coronary sinus aneurysms generally ruptureinto theright atrium.Left coronarysinus aneurysms are extremely rare, but they may rupture in to the pericardium, resulting in cardiac tamponade and death if not quickly recognized. Echocardiography is very accurate and reliable tool in diagnosing a sinus of Valsalva aneurysm when correlated with clinical findings. 8 In addition Computed tomogram angiography and magnetic resonance imaging also have been reported usefulin diagnosingthe sinusof Valsalva. 9-10 Cine phase contrast MRI can be used for assessment of insufficiency andshunt flow.
Sinuses of Valsalva aneurysms have one of three basic pathologic patterns. 5  Unruptured aneurysms may cause distortion and obstruction in the right ventricular outflow tract. Dissection of the aneurysm in to the cardiac tissue may occur, causing obstruction or destruction of adjoining structures. Aneurysm may compressthe interventricular septum, resultingin complete heart blockwith subsequent dizziness and syncope. Coronary artery compressionmay occurproducingmyocardialischemia and chest pain. Occasionally a patient with unruptured si-nus of Valsalva aneurysm presents with symptoms related to chronic aortic regurgitation.  A slowly enlarging smallperforation develops a fistulous tract in to the right ventricle and presents with a small left to right shunt. Major risk is infective endocarditis an extension of rupture with an increased shunt. Patient may remain asymptomatic for several years because of haemodynamic adjustment. However, as the degree of shunting increases symptoms related to volume overload, such as dyspnoea and exercise intolerance develops.  An aneurysm that actuallyruptures isoften heralded by the sudden onset ofdyspnoea and severe chest pain .Following this initialsymptomatic period, the patient may become asymptomatic even without treatment as thebody adjusts haemodynamically to the left to right shunting. However asthe shuntingand volume overload overcome the compensatory mechanisms, symptoms ofcongestive heart failure result.
Ruptured sinusof Valsalvaconnects thehigh pressure reservoir of the systemic circulation with the low pressure system of the pulmonary circulation resulting in a systolic-diastolic left to right shunt. There is volume overload of the left atrium, left ventricle and the aortic root that is proportional to the shunt volume. Amountof shuntvolume is influenced bythe diameter of the rupture and by the level of pulmonary vascular resistance.Alarge shunt causes a large volumeof blood that is shunted from the systemic circulation, into the pulmonary circulation. The inevitable consequence of this ispulmonary congestionand rapidlydeveloping left sided heart failure.

Physiological changes during pregnancy;
During normalpregnancy the totalblood volume increases by 40% and plasma volume increases 45% and red blood cell volume increases by 25%, accountingfor therelative anemia of pregnancy.CentralVenous Pressure (CVP) andPulmonary Capillary Wedge Pressure (PCWP) are unchanged in pregnancy. 11 The cardiac output increases approximately by 45-50% and systemic vascular resistance decreases by 35%. This elevation in cardiac output is sustained until delivery. The rise is accomplished by an increase in both heart rate and stroke volume. In supine position aortocaval compression leads to decrease in venous return, cardiac output, and uterine blood flow after 28 weeks of pregnancy. Systolic blood pressure decreases slightly whereas significant decrease in diastolic blood pressure occurs. Associated with the expansion in blood volume is a minimalincrease in left ventricular end diastolic volumesassessed by Echocardiography. 12 Ejection fraction remains constant.
Pain and apprehension of labor further increase strokevolume and cardiac outputby 45%over prelabor values. 13 Additional stresses are imposed by uterine contractions,which cause,in effect, an autotransfusion. With each uterine contraction, central blood volume increase by 10 to 25 percent. 13 After delivery, central blood volume also increases. Emptying of the uterus relieves obstruction of the venacava and aorta, resulting in a marked increase (up to 80% of prelabor values) in stroke volume. Therefore pregnancy is a state that places haemodynamicstrain onthe cardiovascular system and can be risky inwoman withunderlying cardiac disease. 14 This case was typically of the congenital type and perhaps the rupture of aneurysm of sinus of Valsalva has taken placeduringvaginal delivery of earlier pregnancy. Rupture might have been precipitated by the hyperdynamic state of labor coupled with harmonicallyinduced changes in the mechanical properties of connective tissue. Shunt diameter was not increased and there was no evidence of further rupture or there is no evidence of infective endocarditits or increase in levels of pulmonary vascular resistance. Cardiovascular system is progressively stressed during pregnancy, prelabor, and postpartum period. Increase in cardiac output willresult in volume overload of left atrium, left ventricle and increase in shunt volume. Patients with limited cardiacreserve may experience cardiac failure during this time. 14 Treatment of acute congestive cardiac failure duringpregnancy aims in reducing cardiac work, bed rest, decreasing preload with diuretics, improvingcardiac contractility with digitalis and other agents, reducing after load with vasodilators. 15 In this case an elective caesarean section under general anaesthesia was planned for her since the patient wasalready haemodynamicallycompromised. The haemodynamic changes occurring duringlabor would have exacerbated the left to right shunt and perhaps extended the aneurysmal tear. In vaginaldelivery cardiac output increases 80% of the prelabor values as compared to 50% in caesarean section. 16 Although epidural anaesthesia would have decreased the systemic vascular resistance (SVR) secondary to sympathetic nervous system blockade and would have decreased the cardiac output, nevertheless decrease in S.V.R is not predictable and not easy to control therefore should probably not to be selected over general anaesthesia. Epidural anaesthesia is associated with an increase in only 40% in cardiac output andgeneral anaesthesia, with an augmentation of only 25%. 17 Our goals of management in this case were: Maintain haemodynamic stability and cardiac output. Anaesthesia was inducedin supine position with 10°-15°left lateral tilt. To attenuate pressure response lidocaine 1.5 mg.kg -1 was given prior to laryngoscopy. Although succinylcholine canabruptly increasethe parasympathetic nervous system activity and could theoretically haveadditive effects with digitalis, we preferred succinylcholinebecause ofour clinicalexperience. Anaesthesiawas maintainedwith positive pressure ventila-tion as it decreases the preload thereby improving the cardiac function. Vecuronium was preferred due to bettercardiac stability. Low doses of opioidswere given for analgesia. The patient was monitored in ICU post operatively.
Normally there is a large increase in total blood volume and a significant increase in cardiac output in pregnancy which places haemodynamic strain on the cardiovascular system. This excessive burden further increases in a patient with left to right shunt resulting from ruptured aneurysm of rightsinus ofValsalva. Caesarean section under general anaesthesia appears to be an optimalmanagement ofdelivery in pregnancy of such patients. The definitive surgical repair of cardiac defect can beundertaken subsequentlydepending upon the condition of the patient.